In a utility vehicle disclosed in U.S. Pat. No. 8,454,041, to a front frame which is a front end member of left and right main frames constituting a vehicle body, a suspension device is attached via a reinforcing frame. To the front frame and between left and right steering front wheels, there is attached a differential unit to which power from an engine is transmitted. Left and right drive shafts extending to the left and right from the differential unit are coupled respectively to the left and right steering front wheels via knuckle arms. An upper end portion of a shock absorber is coupled to an upper portion of the front frame via a mount and around an intermediate portion of the shock absorber, a coil spring is fitted. To respective leading end portions of an upper arm and a lower arm, the knuckle arms rotatably supporting the steering from wheels are supported to be pivotable about vertical axes. Further, base end portions of the upper arm and the lower arm are supported to a lower portion of the front frame to be pivotable about horizontal axes. Each arm is coupled, via a ball joint attached to its leading end, to the knuckle arm. To the knuckle arm, there is coupled a tie rod of a steering unit for pivotally operating the steering front wheel. The steering unit is configured as a hydraulic cylinder type or a rack-and-pinion type.
In a utility vehicle disclosed in US Publication No. 2007/0214818A1, a base frame which is a major constituent member of a vehicle body is comprised of a pair of left and right side members and a cross member which interconnects the pair of left and right side members. The respective side member comprises a tube having a rectangular cross section and extends in a vehicle body front-rear direction. Front end areas of the pair of left and right side members have a narrowing distance therebetween, thus forming a front frame which supports driving front wheels steerably.
A front frame supporting the steerable driving front wheels mounts a differential unit, and a pair of left and right drive shafts extending from this differential unit extend upwardly of the front frame. The respective drive shaft incorporates a constant velocity joint. Provided the size of the front wheels being fixed, the lower the ground clearance of the differential unit, the smaller the slope angle of the constant velocity joint, thus, the smaller the load applied to the constant velocity joint. Further, the lower the ground clearance of the differential unit, the lower the gravity center of the vehicle body, thus, the better the traveling stability. Moreover, the steering unit for steering the front wheels is disposed adjacent the upper side of the differential unit. Thus, the lower the ground clearance of the differential unit, the larger the space available for mounting the steering unit, so the steering unit can be mounted at an appropriate position.